In high school, our QB would constantly change his cadence so that when it meant something-- like in a decision play, where he'd say black 14 to go to the 4 hole, or green 13 to go to the 3 hole for instance, depending on the defensive lineup--they wouldn't pick up on it because he'd been doing it the whole game.

Seems like Rodgers only uses one cadence for when they actually snap the ball and uses another color for when he is trying to draw a defense to figure out their play and make adjustments or to be aware.

If it's the same thing every time, it's a snap count/ filler. If it's something different, it could be code for play calling or something and you're not supposed to know what it means unless you are on the team or have access to the plays.

There was a blog post about this on jsonline. They asked Brett Favre if they meant anything. In true Brett fashion, he gave a rambling and fairly incoherent answer. If I remember correctly, the color means absolutely nothing, but the number usually identifies the defensive formation. I'll see if I can dig up the blog post.